Grate-bar section.



E. A. WILDT.

GRATE BAR SECTION.

APPLICATION FILED JAN. 25. 1913.

Patented May 4 1915.

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E. A. WILDT.

GRATE BAR SECTION.

APPLICATION FILED JAN. 25. 1913.

1,138,339. Patented May 4, 1915.

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EDWARD A. WILDT, 0F SORANTON, PENNSYLVANIA.

GRATIS-BAR, SECTION.

Application filed January 25, 1913.

To all whom it may concern.

Be it known that I, EDWARD A. WILDT, a citizen of the United States, residing at Scranton, Lackawanna county, State of Pennsylvania, have invented certain new and useful Improvements in Grate-Bar Sections; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My present invention relates to improvements in the construction of grate bars in thelgrates of furnaces intended to burn fine coa The invention is particularly directed to a grate construction which will admit of the practical utilization of a refuse of anthracite coal lmown as slush, which is the material left over after all the merchantable sizes of coal have been recovered from the crushed coal after it has been brought from the mines. This slush is good fuel for steam boilers when the orifices in the grate are small and considerable pressure is maintained upon the air beneath the grate. It is of advantage to have comparatively few 7 very small openings in the grate through which the air blast is maintained as under such conditions the air having considerable velocity blows on the surface of the coal and frees it from ash, permitting a direct contact of the air with the burning coal .and producing a very hot fire. When the old style of grate with numerous large openings, is used, with a comparatively low pressure draft, the air merely floats up through. the coal retarded by the accumulated covering of ash and the result is a slow fire.

The width of the apertures in the grate bars which will permit of the advantageous burning of this fine coal should be less than the amount of expansion leeway which is required in the ordinary length grate bar, and, therefore, some provision must be made by which a large opening at the end of the grate bar can be avoided and an even draft provided throughout the whole surface of the grate. An allowance of one-quarter of an inch is usual for the ordinary length of grate-bar, while the slots in the grate bar which I prefer to use in order to produce the best results are about 1/32 of an inch wide, and it will, therefore, appear that the opening at the end of the bar before expansion takes place would be at least 1/4 of an inch Specification of Letters Patent.

Patented May a, 1915.

Serial No. 744,227.

in width and would admit of the escape of the air in great volume at this point and preclude an even distribution of the draft throughout the various apertures of the grate.

It is therefore an object of this invention to provide a construction of the grate bars which shall be simple and provide for the expansion without leaving openings in the surface of the grate of greater area than the normal opening between the various segments of the bars.

I have illustrated in the accompanying drawings a grate structure in which the grate bars are provided with an end leaf which slidably engages the journal bars of the grate frame and is capable of movement toward and from the journal bar by an amount sufficient to accommodate the expansion without affording an opening, between it and the journal bar, through which the draft could escape, and in which one end of each of the grate bars is restrained against axial movement and the other end is journaled to the aforesaid slidable leaf in order that this leaf may move axially with the grate bars as they expand or contract and maintain its normal separation from the ends proper of the grate bars.

In the drawings, Figure 1, is a side elevation of a grate frame showing the grate bar journals which I employ to restrain the ends of the grate bars against axial movement during expansion and contraction; Fig. 2, is a plan of the grate shown in Fig. 1 with a portion of its middle broken away; Fig. 3, is a vertical cross section taken on line 3-3 of Fig. 2; Fig. 4, is an elevation of the end leaf; and Fig. 5 is a section taken on line 55 of Fig. 3.

Referring to the drawings, each grate bar is built up of intermediate segments A and end-plates B and G held together by tierods D upon the ends of which nuts E, E are drawn up in depressions F in the outer walls of the end plates B and C.

The end plate B of each of the grate bars is provided with a trunnion G which is turned up with an annular projecting bead H and the end plate C is provided with a trunnion J which is turned up with an annular groove near the plate C and an extended bearing portion toward its end.

The grate frame is inade up of the journal side bars L and M and the end bars N and O. I

The journal bar M of the frame is provided with journals P which have annular channels Q to receive the beads H upon the trunnions G of the grate bars and I have found it convenient to make the upper halves of the journals P in two pieces R and S, the piece R being the upper half proper of the bearing and the piece S being used to lock the piece R in place. It will now be seen that the ends of the grate bars which are j ournaled in the journal bar M cannot move axially in these journals.

The journal bar L is provided with smooth journals similar to journals P in journal bar M, though without the channels Q, and the cylindrical outer portions of the trunnions J projecting from the plates 0 of the grate bars rest in these ournals and are permitted axial movement therein when the grate bars expand or contract. The journal bar L is provided with a flange T upon its inner face and upon this flange T, the overhanging flanges U of the end leaves V, best illustrated in Figs. 3 and 4-, rest.

Each end leaf V is provided with a yoke V in its lower edge which fits into the annular channel K in the trunnion J of the end plate C of the grate-bar, and it will therefore be seen that when the grate bar expands or contracts, the end leaf V will travel axially with it, the overhanging flanges U of the leaf V sliding down upon the flange T of the journal bar L and affording no air space between the leaf and journal bar at any position which the end of the grate bar might assume during expansion and contraction.

It will also be seen that the air space afforded between the leaf V and the end plate C of the grate bar will remain of constant width as the leaf travels axially of the grate bar. The leaf V has no rotative movement with relation to the journal bar L, but simply slides toward and from this journal bar, while the grate bars may be oscillated in the usual manner.

With this construction, it will be seen that expansion and contraction of the grate bars may take place without appreciably varying the distribution of the apertures throughout its surface, and without having apertures at one point of greater area than those at another, which would permit of an unequal issuance of the forced draft; and that the grate may be shaken and dumped in the usual way without interfering with the expansion arrangement provided to insure against the undue escape of the draft.

lVhat I claim and desire to protect by Letters Patent is:

1. The combination with a grate frame, of a grate bar trunnioned for rocking upon said frame and an axially slidable lap expansion joint between said bar and said f 'ame, one element of sald lap joint being carried by said bar and being free from rostrained from axial movement relatively to said frame, and the other end of said bar making an axially sildable lap expansion joint with said frame; substantially as described.

l. The combination with a grate frame, of a grate bar trunnioned for rocking upon said frame, one end of said bar being restrained from axial movement relative to one side of said frame, and an expansion leaf making a slidable lap joint with the other side of sai d frame and engaged with the free end of said bar to be moved axially therewith as said bar expands or contracts; substantially as described.

5. The combination with a grate frame, of a grate bar trunnioned for rocking upon said frame, the trunnion at one end of said bar being provided with a thrust collar and held against axial movement in a partable journal in said frame, and the trunnion upon the opposite end of said bar being free to move axially of said journal in said frame, and an expansion leaf making a slidable lap joint withthat side of said frame in which said axially movable trunnion is journaled, said leaf being engaged in an annular channel in said axially movable trunnion to be axially moved thereby; substantially as described.

6. The combination with a grate frame, of a grate bar built up of a series of segments spaced apart and tied together by tie rods and trunnioned to rock upon said frame, one end of said bar being restrained from axial movement relative to one side of said frame, and an expansion leaf making a slidable lap joint with the other side of said frame and engaged with the free end of said bar to be moved axially therewith as said bar expands or contracts; substantially as described.

In testimony whereof I affix my signature, in presence of two witnesses.

EDWARD A. /VILDT. lVitnesses:

.losnrn S. MILLER, C. A. KEEGAN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

